To give an idea of how a move from 90nm to 65nm affects performance, we performed some benchmarks on both versions of the Athlon 64 X2 5000+. As can be seen in our results, in most cases the 65nm version of the processor actually has less performance compared to the 90nm version. This is primarily because AMD has made some modifications to the L2 cache, and so the L2 cache latency has actually increased from 12 cycles to 14 cycles. The latency of the L1 cache, on the other hand, remains the same along with the latency of the memory controller.

AMD has stated that the larger latency will allow them to increase the size of the L2 cache in future processors. This does not, however, mean that AMD will necessarily release a 65nm CPU with a larger L2 cache, just that they have the possibility of doing so.

Here are the results of our tests: